Oxygen atoms from Earth bombard the moon

For over 2 billion years, bits of atmosphere have traveled to lunar surface, data suggest

OTHERWORDLY OXYGEN Oxygen atoms escape from the upper atmosphere into Earth’s magnetosphere (blue lines), researchers propose. For five days each lunar cycle, the moon passes through the magnetosphere and is bombarded by oxygen (green haze).

Osaka University, NASA

Life on Earth may have made its mark on the moon billions of years before Neil Armstrong’s famous first step.

Observations by Japan’s moon-orbiting Kaguya spacecraft suggest that oxygen atoms from Earth’s upper atmosphere bombard the moon’s surface for a few days each month. This oxygen onslaught began in earnest around 2.4 billion years ago when photosynthetic microbes first flourished (SN Online: 9/8/15), planetary scientist Kentaro Terada of Osaka University in Japan and colleagues propose January 30 in Nature Astronomy.

The oxygen atoms begin their incredible journey in the upper atmosphere, where they are ionized by ultraviolet radiation, the researchers suggest. Electric fields or plasma waves accelerate the oxygen ions into the magnetic cocoon that envelops Earth. One side of that magnetosphere stretches away from the sun

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